Writing instruments were in evidence in prehistoric cave drawings. While they, no doubt, facilitated the spread of communicable diseases, they have not been commonly recognized as instruments of transmission. A more commonly recognized instrument of disease transmission is the flush handle associated with a toilet and, to a lesser extent, door knobs or push-plates. Our daily lives are replete with opportunities for infection simply through the communal use of familiar objects which we do not find ominous because of their familiarity. A study demonstrating the potential for communicating an infection via handled objects has been conducted using card-playing college students as subjects. The study demonstrated that the communication of a viral infection, the common cold, was greater when the subjects handled common playing cards, than through the much more intimate contact of kissing. The results were attributed to the card players with colds effectively transmitting the virus to the non-infected players by contaminating the cards with the virus where it transfers to the hands of the non-infected players, whereupon the non-infected players infected themselves when they rubbed the mucus membranes of the nose and eyes.
Current events are often centered around communicable diseases and the suffering they are causing, and sometimes death. Many infections associated with the restaurant industry are apparently communicated to the public through the common use, by the subjects, of an object used initially by the diseased subject with unclean hands. Writing pens are among the most commonly used public items and are not thought of as instruments of communicable diseases. The common habit people have of unconsciously putting pens into their mouth and the open space between the end of the shaft and the small cap on the upper end of the pen, which would maintain a furtile environment for a host of pathogens, makes them one of the most potent sources of communicable disease. Other common habits such as putting fingers in the mouth, rubbing the nose, rubbing the eyes, and scratching or touching open wounds, all make the hands a potent source of infection. Also, other commonly used items, such as door knobs, flush-handles on toilets, by contaminated hands, are a source of communication of disease pathogens.
The potential for the transmission of disease via common items becomes greatly enhanced when visiting or working in an environment where the focus of that environment is treating diseased individuals. In fact, the common writing pen is probably the weakest link in a sterile environment in the health-care field.
Inks typically have a low vapor pressure to allow them to dry quickly and prevent smudging. This attribute also makes autoclaving the ink, as set forth in U.S. Pat. No. 5,161,971 to Neimer et al, at necessarily high temperatures without damaging the ink, impossible. Further, it is not common for the public offices of any description, other than health-care, to have an autoclave available for sterilizing a writing pen.
U.S. Pat. No. 3,482,258 to Steen addresses a method for maintaining a sterile ink supply. While that is important in maintaining a free-flowing ink supply, it was not intended to address the problem of communication of disease pathogens between users of the writing device.
Ink repellent coatings have been developed for writing pens, as shown in U.S. Pat. Nos. 2,979,030 to Harrington and 3,030,925 to Dyson, to prevent ink from adhering to the pen which could soil documents being created or edited with the writing pen, or soil the user's fingers and clothing.
Others have used pens as part of a novel, multi-use item for grooming, as shown in U.S. Pat. No. 4,768,531 to Broussard. The Broussard pen was apparently meant as a handy travel utility.
A pen which emitted a fragrance intended to adjust the sensitivities of the user to a more pleasant memory is the subject of U.S. Pat. No. 3,888,416 to Lin. The inventor suggests that the fragrance emitted by the pen would help the user forget unsettling surroundings which have characteristic odors, such as a hospital or a sick ward.
A perforated tape that delivered a sterilizing liquid or foam from an underlying sponge area is the subject of U.S. Pat. No. 4,832,042 to Crace. Such a tape would be common knowledge to anyone who has ever used an adhesive bandage and had the previously applied antiseptic seep through the holes in the top to soil their fingers. It would prove impractical for use under any, but very specialized, conditions where the liquid or foam deposited on the individual contacting the tape would not cause a problem being transferred to other objects being handled by the individual. Additionally, the drying of the solution in the sponge layer and/or repeated use, would rapidly render the tape ineffective.
In spite of attempts to modify writing instruments for a variety of purposes, it is believed that no writing pen has ever been proposed which would conveniently and consistently prevent the writing pen from becoming a vehicle for the transportation of a broad spectrum of communicable pathogens throughout the useful life of the writing pen without notably soiling the user. In addition, it is not believed that commonly used public items, such as door knobs or flush-handles on toilets, have been modified to resist the growth of pathogens placed on those objects by touching and thereby reduce the potential of them becoming vehicles of infection.
It has been customary to add preservatives to plastics to protect the plastic itself against attack by microorganisms. Plastic additives such as plasticizers can affect the susceptibility of a plastic to microbes. The test typically associated with a desire to protect the plastic, test the ability of fungi to use the polymeric material as a food source and the ability of stain-producing microorganisms to stain the polymeric material, is termed "the pink stain test". Other tests, such as a soil burial or humidity cabinet test, may be done. None of these tests or preservatives are directed at viruses which can live only in vital tissue, but may use a plastic device as a vehicle to infect. It is not believed that any attempt has been made to address the viability of human pathogens on commonly used objects such as writing pens, door knobs, or flush-tank handles.
Currently evolving communicable diseases such as AIDS define a need to develop some protection from disease pathogens omnipresent on commonly used public items. While AIDS is currently not as easily transmitted as many other viral infections, the incidence of recorded infections has risen from 1 million recorded cases world-wide, to a current figure of 14 million, in a relatively short period. The ability of the AIDS virus to undergo rapid mutation could produce a strain which readily infects, as cold or measle viruses do.